Base catalyzed isomerization of allyl phosphonate diesters to vinyl phosphonate diesters

Abstract

Allyl phosphonate diesters are converted to vinyl phosphonate diesters by isomerization with a catalytically effective amount of one or more metal hydroxide catalysts.

What is claimed is: 
     
       1. A process for the preparation of a vinylic phosphonate diester compound of the formula: ##STR6## from a corresponding allyl phosphonate diester of the general formula: ##STR7## which comprises isomerizing said allyl phosphonate diester at a temperature of from about 0° C. to about 150° C. with a catalytically effective amount of one or more metal hydroxides, selected from the group consisting of alkali metal and alkaline earth metal hydroxides, wherein: R 1  and R 2  are the same or different and are alkyl, cycloalkyl, arylalkyl or alkylaryl, either unsubstituted or substituted with one or more substituents which are inert under the process conditions.   
     
     
       2. A process according to claim 1 wherein R 1  and R 2  are the same. 
     
     
       3. A process according to claim 2 wherein R 1  and R 2  are unsubstituted. 
     
     
       4. A process according to claim 3 wherein R 1  and R 2  are alkyl having form 1 to about 8 carbon atoms. 
     
     
       5. A process according to claim 4 wherein R 1  and R 2  are alkyl having from 1 to about 4 carbon atoms. 
     
     
       6. A process according to claim 5 wherein R 1  and R 2  are methyl or ethyl. 
     
     
       7. A process according to claim 1 wherein said one or more metal hydroxides are selected from the group consisting of alkali metal hydroxides. 
     
     
       8. A process according to claim 7 wherein said one or more alkali metal hydroxides are selected from the group consisting of sodium hydroxide and potassium hydroxide. 
     
     
       9. A process according to claim 8 wherein said allyl phosphonate ester is isomerized with potassium hydroxide. 
     
     
       10. A process according to claim 1 wherein the amount of said metal hydroxide is at least about 1 mole percent based on the total moles of allyl phosphonate diester. 
     
     
       11. A process according to claim 10 wherein the amount of said metal hydroxide is from about 1 to about 25 mole percent. 
     
     
       12. A process according to claim 9 wherein the amount of said metal hydroxide is from about 10 to about 20 mole percent. 
     
     
       13. A process according to claim 1 wherein said isomerization temperature is from about 0° C. to about 100° C. 
     
     
       14. A process according to claim 1 wherein said allyl phosphonate compound is a liquid under the isomerization conditions and said isomerization is carried out neat. 
     
     
       15. A process according to claim 1 wherein said isomerization is carried out in a solvent which is nonreactive with the reactant and catalyst under the process conditions. 
     
     
       16. A process according to claim 15 wherein the solvent is selected from the group consisting of benzene, monoalkylated benzene, dialkylated benzene and alkanols. 
     
     
       17. Process according to claim 13 wherein said solvent is an alkanol having from 1 to about 6 carbon atoms. 
     
     
       18. A process according to claim 1 wherein the isomerization is conducted at ambient temperature. 
     
     
       19. A process according to claim 15 wherein the the isomerization is performed at the reflux temperature of the solvent. 
     
     
       20. A process according to claim 1 wherein the vinylphosphonate ester product is isolated by vacuum distillation. 
     
     
       21. A process according to claim 1 wherein said vinylic phosphonate diester product is isolated by solvent extraction. 
     
     
       22. A process according to claim 1 wherein solid one or more metal hydroxides are used. 
     
     
       23. A process according to claim 1 wherein the one or more metal hydroxide compounds are dissolved in a solvent which is non-reactive under the process conditions.